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Microwave-assisted biosynthesis of silver nanoparticles using two marine microalgal extracts and their antimycobacteriosis activity against bacteria isolated from Betta splendens
(2025-12-01)
Manklinniam, Piyapan
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Phunpruch, Saranya
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Sakulkalavek, Aparporn
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Sakdanuphab, Rachsak
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Worananthakij, Worakrit
This study explores the synthesis and antibacterial properties of silver nanoparticles (AgNPs) as a safer, eco-friendly alternative to traditional chemical treatments for bacterial infections. AgNPs were synthesized using aqueous extracts of marine microalgae, Isochrysis galbana and Chaetoceros calcitrans, via conventional and microwave-assisted methods, with the latter accelerating nanoparticle production. Extracts in ethanol, hexane, and acetone were tested, with the ethanolic extract of I. galbana showing the strongest antibacterial effects. The AgNPs exhibited broad-spectrum antibacterial activity against pathogens such as Staphylococcus aureus, Bacillus subtilis, Escherichia coli, Pseudomonas aeruginosa, and fish pathogens like Aeromonas veronii. Microwave-assisted synthesis with ethanolic extracts resulted in the highest inhibition, particularly against fish and tuberculosis-related pathogens, including Mycobacterium marinum. Nanoparticle formation was confirmed using various characterization methods, including ultraviolet-visible (UV-Vis) spectroscopy, X-ray diffraction (XRD), fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM), which revealed crystalline structures. Transmission electron microscopy (TEM) analysis revealed that AgNPs varied in size, with an average diameter of less than 50 nm and all particles being smaller than 100 nm. This research demonstrates the potential of AgNPs as an effective alternative to antibiotics, offering targeted bacterial inhibition while reducing the risk of antibiotic resistance. This makes it a promising approach for treating bacterial infections in ornamental fish.
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Antimicrobial nanolayer films of chloroxylenol–carboxyethylchitosan–modified silver nanoparticles for enhanced surgical suture performance
(2024-07-20)
Chittratan, Pakawat
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Detsri, Ekarat
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Chalitangkoon, Jongjit
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Mathaweesansurn, Arjnarong
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Monvisade, Pathavuth
Antimicrobial surgical suture materials incorporating chloroxylenol-carboxyethylchitosan-modified silver nanoparticles (CECSX-AgNPs) were successfully prepared using the Layer-by-Layer (LbL) deposition technique. Chitosan (CS) was covalently affixed with chloroxylenol as hydrophobic functional groups (PCMX), yielding chloroxylenol-chitosan (CSX) and later hydrophilic acrylic acid onto the CSX skeleton, providing a novel water-soluble antimicrobial agent of chloroxylenol-carboxyethylchitosan (CECSX). 1H NMR confirmed the successful substitution of PCMX and acrylic acid onto CS, with %DS<inf>PCMX</inf> and %DS<inf>AA</inf> of 8.0 and 33.0, respectively. CECSX successfully stabilized AgNPs via the chemical reduction method, resulting in CECSX modified AgNPs. The colloidal solution exhibited a yellowish hue, spherical shape, monodispersity with an average particle size of 4.8 ± 2.4 nm, and a zeta potential value of −20.97 ± 0.03 mV. Minimum inhibitory concentration (MIC) values for CECSX-AgNPs against E. coli (ATCC25922), S. aureus (ATCC25923), and A. baumanii (ATCC19606) were determined as 25, 12.5, and 1.56 mg/L, respectively. Using the LbL deposition technique, CECSX-AgNPs were successfully deposited onto various suture materials including cotton, polyamide, and polypropylene. Remarkably, CECSX-AgNPs coated surgical sutures exhibited the highest bacterial reduction of 99.99 %. These findings underscore the efficacy of CECSX as a high-performance stabilizing agent for AgNPs production, providing outstanding antibacterial activity on diverse surgical suture materials and promoting the wound healing process.
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A new mechanism for resonance Rayleigh scattering detection of minoxidil based on catalytic oxidation of silver nanoparticles
(2022-07-05)
Teerasong, Saowapak
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Praditweangkum, Wiboon
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Chompoosor, Apiwat
This work presents a new method for minoxidil detection based on silver nanoparticle (AgNP) oxidation. Minoxidil, which is a pyrimidine N-oxide, can be reduced to its corresponding pyrimidine via a redox reaction. In this system, acetate buffer serves as a proton source. AgNPs act as electron donors that contribute electrons to the reaction, producing Ag+. Consequently, the sizes and numbers of AgNPs in the system decrease, which results in a decline in their resonance Rayleigh scattering (RRS). By monitoring the RRS intensity at 409 nm, a change in intensity was linearly related to the minoxidil concentration over a concentration range of 0.5 – 5.0 mM. The detection limit was 0.35 mM. This approach is simple and rapid. It is done by directly mixing the drug and AgNPs in an acidic buffer. The reaction was completed within 2 min. This proposed method was successfully utilized for quantification of minoxidil in topical hair-growth formulations.
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PMMA particles coated with chitosan-silver nanoparticles as a dual antibacterial modifier for natural rubber latex films
(2019-02-01)
Suteewong, Teeraporn
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Wongpreecha, Jitrada
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Polpanich, Duangporn
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Jangpatarapongsa, Kulachart
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Kaewsaneha, Chariya
The antibacterial activity in sulphur prevulcanized natural rubber (SPNR) latex film was effectively improved by deposition of poly(methyl methacrylate) (PMMA) particles encircled with chitosan-coated silver nanoparticles (AgNPs-CS). With the focus on a green process, CS was selected as a safe reducing and stabilizing agent for the one-step synthesis of AgNPs-CS (38 nm, +40.4 mV) in an autoclave. The adsorption of small-sized AgNPs-CS directly onto rubber film did not provide an inhibitory effect on S. aureus. It also had a low antibacterial effect on E. coli. This is because of the particles becoming completely/partially submerged into the soft rubber matrix upon drying. Hence, the AgNPs-CS were fabricated as a shell surrounding a rigid PMMA core (496 nm, -30.9 mV). This was done using a heterocoagulation technique prior to coating on SPNR film. The presence of PMMA/AgNPs-CS on the surface of SPNR film effectively increased the surface roughness from ca. 44 to 150 nm. This substantially promoted the antibacterial activity against E. coli and S. aureus by way of contact killing and repelling mechanisms. The cytotoxicity on L-929 fibroblasts was also suppressed. This study would be, therefore, applicable to the development of antibacterial SPNR film with high surface roughness, low cytotoxicity. It could also be applied for other soft substrates.
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Green synthesis of AgNPs coated mesoporous silica nanoparticles using tyrosine as reducing/stabilising agent
(2018-01-01)
Ratirotjanakul, Waranya
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Sioloetwong, Tanapon
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Suteewong, Teeraporn
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Tangboriboonrat, Pramuan
A novel, simple and environmental friendly approach to fabricate silver nanoparticles (AgNPs) on mesoporous silica nanoparticles (MSNs) using tyrosine (Tyr) as biological reducing agent was developed. The functionalization of Tyr with MSNs (Tyr-MSNs) (150 nm in length) by the sol-gel process was confirmed by the characteristic peaks of amino, carboxyl and silanol groups appeared in FTIR spectrum and the change of the zeta potential from 0 mV at pH 2 to -60 mV at pH 12. Then, AgNPs were formed on the surface of Tyr-MSNs (Tyr-MSN@AgNPs) via only reducibility from phenolic group of Tyr and catalytic activity from base at room temperature. TEM images and UV-Visible absorption band at 420 nm supported the obtained AgNPs (18 nm at pH 11) were tightly bound to Tyr-MSNs even after centrifugation at high speed. These Tyr-MSN@AgNPs would be potentially used as drug carrier in biomedical applications.
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Colorimetric detection of glutathione based on phthalic acid assisted synthesis of silver nanoparticles
(2017-11-20)
Detsri, Ekarat
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Seeharaj, Panpailin
A new rapid, sensitive and selective colorimetric sensing platform for the detection of glutathione (GSH) in dietary supplements was developed by phthalic acid (PTA) assisted synthesis of silver nanoparticles (AgNPs). The di-carboxylic functional groups of PTA were used to modify the surface of AgNPs. The resulting AgNPs product was characterized by surface plasmon resonance (SPR) Ultraviolet–visible spectroscopy (UV–vis), Zeta potential analyzer, Fourietransform infrared spectroscopy (FT-IR), Transmission electron microscopy (TEM) and X-ray diffraction analysis (XRD) techniques, demonstrated that PTA is an effective capping agent to stabilize AgNPs. AgNPs stabilized with PTA could cause the strong affinity to GSH. As the GSH concentration increased, the color of AgNPs solutions was gradually changed from yellow to orange and light purple as well as the SPR shifted from 400 nm to 556 nm upon an aggregation of AgNPs due to electrostatic interaction. The proposed colorimetric sensor was exhibited a linear response in the range of 0.1–100 nM (R2 = 0.9992), with low detection limit (LOD) of 0.16 ± 0.01 nM. The sensor showed better precision with relative standard deviation (RSD) of 2.10% and 1.13% for ten repetitive measurements of 25 nM and 75 nM GSH solution, respectively. The sensitivity of AgNPs for GSH detection can be clearly differentiated towards other coexisting substances (Fe3+, Zn2+, Cu2+, K+, Ca2+, Mg2+, glucose, sucrose, cysteine, ascorbic acid and citric acid). The AgNPs colorimetric sensor could discriminatively detect GSH in dietary supplement samples with the recoveries values in the range of 98.5%–103.0%.
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Poly(vinyl alcohol) capped silver nanoparticles for antioxidant assay based on seed-mediated nanoparticle growth
(2017-08-01)
Teerasong, Saowapak
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Jinnarak, Amornrassamee
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Chaneam, Sumonmarn
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Wilairat, Prapin
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Nacapricha, Duangjai
A simple and rapid method for measurement of total antioxidant capacity (TAC) was developed. In this work, gallic acid was used as the antioxidant standard. Poly(vinyl alcohol) embedded silver nanoparticles (PVA-AgNPs) were employed as a colorimetric sensor. The detection principle was based on the seed-mediated nanoparticle growth technique. The PVA-AgNPs act as a catalyst in the reduction of Ag+ by gallic acid by providing nucleation seeds. Ag+ was reduced to Ag° and accumulated on the PVA-AgNP surface, leading to an increase in the size of particles. The absorbance of the colloidal solution was drastically enhanced with a small red shift. Under optimal conditions, a linear response was established between the change in absorbance and the TAC value expressed in terms of gallic acid equivalents. The linear range was from 25 to 200 μM with a detection limit of 22.1 μM. Satisfactory precision was obtained with % relative standard deviation (RSD) of 2.17. The developed sensor was successfully applied for TAC assessment of commercial ginger products. The PVA-AgNP sensor offers rapid analysis (within 5 min) compared to other nanoparticle-based antioxidant assays. Synthesis of the particles and assay involved less-toxic chemicals, and is therefore a “greener” method.
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Sequential injection for determination of gamma-aminobutyric acid based on its effect on second order light scattering of silver nanoparticles
(2016-08-01)
Jinnarak, Amornrassamee
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Anantavichian, Pattarapon
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Intanin, Apichai
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Fungladda, Suchada
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Choengchan, Nathawut
An automated sequential injection (SI) with second order light scattering (SOS) detection for determination of gamma-aminobutyric acid (GABA) was developed. Quantitation is based on electrostatic interaction between GABA and citrate-capped silver nanoparticles (AgNPs). In acetate buffer at pH 3.8, the positively charged GABA induces the nanoparticles to aggregate. This results in a change of light scattering monitored using a spectrofluorometer. In this work, working standard solutions of GABA were prepared in-line by the SI system pumping appropriate volumes of a stock solution of GABA and acetate buffer into a holding coil. Solution of AgNPs was subsequently drawn into the coil. The reaction zone was then transferred to the spectrofluorometer, set with excitation and detection wavelengths at 300 and 600 nm, respectively. Under optimised condition, the SOS intensity was proportional to the concentration of GABA. As a result, a linear curve was obtained in the range of 100–400 mg L−1 GABA, with a lower limit of detection of 39.6 mg L‐1. Good precision of analysis was achieved, with 0.6 and 3.3% relative standard deviation (RSD) for external calibration (n = 5) and standard addition (n = 3), respectively. The developed method was successfully applied for quantification of GABA in dietary supplements (2 samples) and samples of instant green tea (2 samples).
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A novel colorimetric method for detection of gamma-aminobutyric acid based on silver nanoparticles
(2016-06-28)
Jinnarak, Amornrassamee
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Teerasong, Saowapak
A novel, simple and rapid colorimetric method for determination of gamma-aminobutyric acid (GABA) was developed using a negatively charged citrate-capped silver nanoparticle (AgNP) probe. At an acidic pH of 3.8, GABA had a positive charge due to a protonation of amine groups. Therefore GABA could induce an aggregation of AgNPs due to electrostatic interaction. This caused a decrease in the surface plasmon resonance spectra of the colloidal solution at wavelength of 390 nm with a slight red shift. At the same time, the color of the suspension turned from yellow to green upon aggregation. Quantification of GABA was done spectrophotometrically. Under optimum conditions, the method showed a linear calibration in range of 100-500 mg L-1 GABA, with a detection limit of 57.7 mg L-1. The method was successfully applied to measure GABA quantities in dietary supplements.
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Antibacterial activity and nanocomposite properties of monodispersed silver nanoparticles synthesized by the microwave method
(2016-01-01)
Lothongkum, Anchaleeporn W.
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Wongparb, Kornwika
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Sethapokin, Pinthep
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Chaisitsak, Sutichai
Monodispersed colloidal silver nanoparticles (Ag-NPs) were synthesized by a simple and rapid microwave method. A precursor, AgNO<inf>3</inf>, was reduced by ethylene glycol (EG) and N,N-dimethylformamide (DMF) in the presence of polyvinylpyrrolidone (PVP) as a stabilizer or capping agent. It was found that the concentration of AgNO<inf>3</inf> significantly affected Ag-NPs particle sizes. The particle sizes decreased when the concentration decreased from 0.1 to 0.05 and 0.01 M, which corresponded to narrow size distribution of the particle diameters of approximately 60 to 80, 30 to 40 and 10 to 20 nm. The spherical-shaped monodispersed Ag-NPs were obtained by using a volume ratio of EG to DMF of 2.75:2.25, microwave power of 400 W and heating time of 2 min. The volume ratio of EG to DMF and the microwave power influenced the uniformity of the Ag-NPs shape and size, while the heating time had no effect. For antibacterial application, 60-80 and 10-20 nm Ag-NPs showed good disinfection ability against Escherichia coli (ATCC 25922) at the minimum inhibitory concentrations (MIC) of 32 and 16 (μg × ml-1, respectively. In addition, the electrical resistance of the nanocomposites of DMF-loaded Ag-NPs (20-50 nm) without PVP on single-walled carbon nanotubes and polyethylene terephthalate (PET) was measured. As a result, it is obvious that the Ag-NPs help to increase the electrical conductivity of the nanocomposites as the electrical resistance of the Ag-NPs nanocomposites was 4.68 kΩ × cm-2 compared to that of the nanocomposites without Ag-NPs of 8.76 kΩ × cm-2.

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